In my experience, both of these exposures would require
alot of compensation with FP4 [I've never used panf for night work].
Additionally, at the higher exposure times, some underdevelopment
might be helpful, N-1 or more...

I use a chart developed by Gordon Hutchins, and this has worked on
many an occasion. His recommended exposures for fp4 are:

meter => suggested
2s => 3s
3s => 4s
4s => 6s
6s => 12s
8s => 18s
15s => 42s
30s => 100s
1m => 4m
2m => 10m
4m => 24m